Serum 25-hydroxyvitamin D, calcium, and calcium-regulating hormones in preeclamptics and controls during first day postpartum

The evidence for a link between vitamin D and preeclampsia is conflicting. There is a paucity of studies reporting simultaneous 25-hydroxyvitamin D (inactive form) and 1,25-dihydroxyvitamin D (biologically active form). We investigated if levels of serum 25-hydroxyvitamin D, calcium-regulating hormones (1,25-dihydroxyvitamin D, parathyroid hormone), and calcium differ significantly between preeclamptics and controls. On postpartum day one, 98 subjects (44 with preeclampsia, 54 controls) were recruited among women admitted to the postdelivery unit, and their serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, parathyroid hormone, serum calcium, and serum albumin levels were prospectively measured. The majority of participants (70 %) had serum 25-hydroxyvitamin D level < 20 ng/mL; 53 % had < 15 ng/mL. Mean serum 25-hydroxyvitamin D level was similar between cases and controls (p = 0.50). Mean total serum calcium adjusted for albumin and magnesium was similar between cases and controls (p = 0.78). Mean serum 1,25-dihydroxyvitamin D and parathyroid hormone levels were normal, and there were no differences between cases and controls. The only significant differences found between preeclamptic cases and controls were mean body mass index, parity, and season of blood draw. Vitamin D levels did not differ among preeclamptic cases and controls.